"Pooling" in Charleston,SC

originally I am from belgium. I came to Charleston in 2003, bought a house with a pool... Never thought I would be the owner of one. But here I am. :D

I don't consider myself a pro. I have figured out that the basic principles of the pool components are not too difficult. Until I am faced with a problem that is!

My pool is an in-ground pool with an Apollo DE filer Model: VA-52-2 https://goo.gl/photos/7zmXKS89mZN8oPG97
 
Thank you all for the warm welcome. I've already learned a lot. I got the K-2006 testing kit and after a week of feeling intimidated plunged in and tested my water. I discovered that my CYA is off the chart ... 150+ (more like 200) which seems to mean I should replace the water. After the initial shock of the cost fear factor, I am starting to figure out this is the right way to go. Apparently there is a recommended time frame of 5 to 7 years to replace your water? I've been here 12 years ...